1. Field of the Invention
This invention relates to ionizing radiation detectors and, more particularly, to a method of detecting incident ionizing radiation exposure using an Atomic Force Microscope and/or a Magnetic Force Microscope.
2. Description of the Prior Art
Radiation is not visible to the naked eye and yet exposure to certain classes and amounts of ionizing radiation can result in death. Presently, there are numerous different types of dosimeters to monitor exposure to various classes of ionizing radiation and to quantitatively determine the radiation dose. Some of the different dosimeters are: thermoluminescent dosimeters (TLD's), ionization-type radiation detectors, photographic film, Geiger counters and radiochromic materials. Using thermoluminescent dosimeters based on properly doped pellets of calcium fluoride or lithium fluoride usually carries out low-level dosimetery. During heating, the samples emit light whose intensity is recorded thereby indicating a basis of dose to which the material has been exposed.
Increased security concerns have lead to radiation detection systems being positioned at airports, harbors, rail stations, tunnels, highways and borders. There are investigations being conducted to locate dangerous materials that may have been stolen. Routine checks of scrap-metal yards and landfills sites are also being examined for any illegal or accidental disposal of dangerous materials.
Studying and monitoring of ionization radiation and the effects it causes has drawn theoretical and experimental attention for almost a century. Alpha, beta, gamma rays, nuclear decay and particle bombardment from accelerators causes nanometer size physical defects in solids, which cannot be directly seen in optical microscopes due to their small size. The damage indirectly manifests itself in many physical and chemical properties, such as color centers, fluorescence and thermoluminescensce, cross-linkage in polymers, and decontamination of food, etc., which have been widely utilized. The direct observation of the damaged areas was only achieved by chemically etching of the solid and enlarging the induced defects by a factor ranging from 20 to 200 in order for the defects to be seen by ordinary microscopes, see Fleischer, R. L., Serendipitous Radiation Monitors, American Scientist, Vol. 90, 324–331, 2002. Fleischer examined glass and plastic objects that were exposed to radiation over fifty years ago.